[amsat-bb] Re: Quadrifilar Helix antenna question

Dave Guimont dguimon1 at san.rr.com
Mon Jan 23 15:28:43 PST 2012


Go to:


or if you wish call me at 619 275 1495 before 
1800 pacific....I'm in San Diego...

Try my QFH...Many others have built them (years 
ago!!), and found them successful...BUT at 435 
measure the filars +-1/64, and be careful with 
solder joints...and use teflon for the coaxial 
filar.....and I guess obviously, "N" 
connectors......the connector is the most expensive part of the antenna.

I have a friend that lives on a sailboat and 
bought some expensive commercial antenna, and the 
one he built from my dimensions outperforms it....

>QFH are a bear to build, especially on 70 cm 
>unless you’re very , very skilled. I tried 3 
>times and failed 3 times. Finally gave up and 
>went with a standard turnstyle. Still critical 
>tolerances but much easier to make and works 
>lower on the horizon than the QFH. QHtenna used 
>to sell turnstiles (reviewed in QST) but I think 
>they are out of business now. You might also 
>want to consider a moxon. Cebik wrote a nice 
>article on making a moxon based turnstile.  I 
>built one for 70 cm using PVC and like the QFH 
>and eggbeater (with reflector) , it works best 
>on higher passes. If you run out of patience, 
>you might consider the Antennas.us QFH. It was 
>also reviewed positively in QST but I don’t 
>own one. And lastly, omnis are small and simple, 
>but you really need a preamp to avoid a terminal 
>case of frustration. I use the ones from ARR 
>with good results. Mike 
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            73, Dave, WB6LLO
                dguimon1 at san.rr.com

                    Disagree: I learn....

               Pulling for P3E... 

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